1. Field of the Invention
The invention relates to a hydraulic exerciser, more particularly to a hydraulic exerciser which is provided with a pair of reciprocating hydraulic cylinders.
2. Description of the Related Art
Hydraulic exercisers, such as hydraulic steppers and rowing machines, are known in the art. Referring to FIG. 1, a conventional hydraulic stepper is shown to comprise a base (A1) and a pair of driven units (A2) which are mounted pivotably on the base (A1). Each of a pair of hydraulic cylinders (A3) has a cylinder body, which is mounted pivotably on the base (A1), and a piston rod which has one end that is mounted pivotably to a respective one of the driven units (A2). A support (A4) is secured on the base (A1). A linkage (A5) is mounted rotatably on the support (A4) and has two oppositely extending arms which are connected pivotably to a respective one of the driven units (A2). The linkage (A5) permits reciprocating movement of the driven units (A2), that is, downward movement of one of the driven units (A2) results in the corresponding upward movement of the other one of the driven units (A2).
The hydraulic cylinders (A3) resist movement of the driven units (A2) and contain hydraulic fluid which flows from one end of the cylinder body to the other end of the same via a fluid hole that is formed in a piston (not shown) which is disposed slidably inside the cylinder body whenever the respective piston rod is extended from or is retracted into the cylinder body. The fluid hole is designed so as to control the flow of hydraulic fluid in a predetermined direction, thereby permitting the generation of a resistance to the movement of the driven units (A2).
Note that in the conventional hydraulic stepper, the maximum vertical displacement of the driven units (A2) is limited by the linkage (A5). The linkage (A5), however, is a necessary element of the conventional hydraulic stepper since it is responsible for the reciprocating action of the driven units (A2).